Reduction Fire Part 2

Well, we didn't get the results that we expected in that reduction fire a couple of weeks ago.  At the right is a picture of what we saw when we opened up the kiln.  Those dark pieces (look at the bottom row) are supposed to be a green ash glaze.  Needless to say, they are not green and that doesn't look like an ash glaze!

We also think that it got hotter than cone 6.  It was definitely hotter on the bottom than the top.  We can tell by looking at the cone packs on the bottom and top shelf.  The cones at the bottom melted more than the ones at the top.  Each pack has a cone that melts at cone 5 temperature, a cone that melts at cone 6 temp, and a cone that melts at cone 7 temperature from left to right.  The left cone should be completely over, the middle on should be bent, and the right one should be just barely bent.  These are way farther over than that indicating that the temperature was high.

Some of the pieces were a pleasant surprise here too.  The blue glaze that Allen and I used a lot of turned a very cool kind of tan color on some pieces.  Normally it ends up being kind of blue gray.  Check out the small lidded casseroles on the top shelf.  Those are Allen's and they look really good.  (They are kind of hard to see since they are in the shadows.)

On the second (from the top) shelf are other examples.  Those are mine, and one of those pieces is really blue and the other is more tan.  This is an excellent example of how two pieces with the same clay and the same glaze on the same shelf can come out looking different.  Stuff like this will drive a person crazy!

So what now?  We are experimenting with the pieces with the unfortunate "ash" glaze.  What can we dip them in to re-fire and make them prettier?  So far, there are several options that are an improvement over how they look right now.  Shoot!  Even re-fired at oxidation with no additional glaze they look better than they did coming right out of the gas kiln.

Reduction Fire

Several of us who work in Allen Griffin's studio in Shelby (Allen Griffin, Vicki Halloran, Ronnie Blackburn, and I) have been working on pieces to fire in our friend--and learned colleague--Gene Young's gas kiln.  In a gas kiln, one has the opportunity to fire at reduction, which means that the oxygen is removed from the atmosphere in the kiln at certain points in the firing.  The glazes and clay bodies react differently than they do at oxidation, which is what we normally do in the electric kiln at the studio.

This project involved making the pieces, bisque firing them, glazing them with the glazes that generally give good results in this type of kiln, and then packing them carefully for transport.  On Friday, Allen, Ronnie, and I took everything over to Gene's to load the kiln.


Before we could load, we had to do some work on the kiln shelves to remove some old glaze so that our pieces wouldn't stick to the shelves.  Checking out the shelves is a normal step before every fire, but this time, the work was more involved than we anticipated.  At the left, Ronnie and Allen are working hard to try to finish before the rain started.


Once the shelves were fixed, we sorted all the pieces by size inside the shed to keep them out of the rain.

When you load a kiln, it is best to put pieces of the same height on a shelf.  The idea is to use the space in the kiln as efficiently as possible.  In other words, you try to cram as much stuff inside as possible without allowing any of the pieces to touch.

This kiln is deep enough for two shelves to fit front to back.  Starting with the bottom shelf in the back, we worked our way forward and up shelf by shelf.  

At the right, the kiln is loaded and ready to go.


In my next post, I will let you know how it went.  I hope to have some pictures of some really good looking pottery!